The invention described herein arose in the course of, or under, contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of the Lawrence Livermore National Laboratory.
The present invention relates generally to the field of lasers and more particularly to a system for dividing the output of a laser such that the output may be directed to several different receiving devices.
In many applications of lasers it occurs that laser subsidiary devices are arrayed and utilized in a manner analogous to serial and parallel arrangement of electric components in electrical circuitry. As an example, a laser beam may be generated in a laser generating device and then transmitted through one or more laser amplifying devices to increase the power of the laser to be sufficient for its intended purpose. As another example, a laser beam may be subdivided such that it may be directed to several different receiving devices. To accommodate these usages various means have been developed to combine the output of several laser generating devices into a single beam. Likewise, means are available for dividing the output of a laser beam into subdivisions thereof, the simplest of which is to physically divide the beam by inserting an optical component, such as a mirror, partially into the path of the beam such that a portion continues on its original path while a remaining portion is altered into a different path by the inserted optical component. However, this simple method, while being quite adequate for some purposes, results in subdivided portions of the beam that are smaller in cross section than the original, and this is unacceptable in many applications.
Another frequently employed prior art method for dividing a laser beam is to pass the beam through a partially silvered mirror such that a portion passes through the mirror and a portion is reflected from the mirror. This method is particularly useful for generally low power laser applications.
Still another prior art method for dividing a laser beam is to cause the laser beam to have orthogonally polarized components such that when a polarized filter is inserted into the path of the beam one component of the beam may pass therethrough and another component of the beam cannot pass therethrough. This method is particularly useful for precision applications such as laser interferometry. However, it is not practical in higher power laser applications due primarily to the fact that the generation of laser beams having specific polarizations runs counter to the objective of causing the beam to have the greatest power content possible given the generating environment.
Clearly, it would be desirable to have a means for dividing a laser beam into a multitude of separate laser beams which could be used in conjunction with high power beams and which is relatively simple in construction such that it can be made to be small in size and generally more robust then prior art comparable devices. Similarly, it would be desirable to have such a means which could be constructed such that different subdivisions of the beam could have differing power content such that a variety of different applications could be supplied by a single laser.
To the inventors' knowledge, no prior art means for dividing a high power laser beam into a large number of subdivided parts has met the requirements described above. All prior art means have either been extremely complicated in construction or else they have been fragile and difficult to construct such that each of the subdivided portions of the beam has the power content desired for that portion.